1. Field of the Invention
The present invention relates to a cleaning device that is used in an image forming apparatus such as a printer, a copying machine, and a facsimile.
2. Description of the Related Art
In a recent image forming apparatus, there has been an attempt to extend the life of the apparatus by suppressing the amount of scraping of a photosensitive drum (image bearing member) to be ¼ of the scraping amount of the related art. When the scraping amount becomes ¼ or less of the scraping amount of the related art, the life of the apparatus, which is normally sufficient to print thirty thousand sheets to seventy thousand sheets in the related art, increases to be sufficient to print one hundred twenty thousand sheets to three hundred thousand sheets.
During such an extended life of the apparatus, even in a cleaning device that cleans a photosensitive drum, a cleaning blade needs to be stably pressed against the photosensitive drum to ensure a long life time. As this configuration, there is proposed a configuration in which a tension coil spring is hooked to the end of a metal sheet of the cleaning blade so as to equalize the pressure (see Japanese Patent Laid-Open No. 11-38846).
However, Japanese Patent Laid-Open No. 11-38846 discloses a configuration in which the tension coil spring is hooked to the end of the metal sheet of the cleaning blade so as to press the cleaning blade against the photosensitive drum. For this reason, the center pressure of the cleaning blade in the longitudinal direction is weakened, so that the scraping becomes uneven due to the difference in the scraping amount between the center and the end of the photosensitive drum. In particular, in a recent high-quality image forming apparatus, the slight uneven scraping leads to a defective image, and hence the image of the uneven scraping appears as shading when outputting a halftone uniform image.
It is thus desirable to provide a cleaning device capable of adjusting the pressure distribution in the longitudinal direction while equalizing the pressure from a cleaning blade to an image bearing member for a long period of time with a simple configuration, and to provide an image forming apparatus including the same.